“Postbiotics” & smart toilet paper: Future platforms in digestive health?

22 Jun 2018 --- “Postbiotics” – the metabolic byproducts produced by our gut bacteria – and even smart toilet paper are some of the ideas within digestive health put forward following novel research at King's College London into the function of gut bacteria. Linked to a range of health-related conditions, the gut microbiome has been a topic of growing interest. However, although there is an established list of gut bacteria, their function in the gut has remained reasonably unknown. The researchers have set out to create a database of fecal metabolites – compounds produced by the gut microbiome – in an attempt to shed light on the relationship between what we eat, the way it is processed by our gut microbes and how we accumulate abdominal fat. 

The researchers found that the fecal metabolome is influenced mainly (80 percent of its variance) by environmental factors, among which are the gut microbial composition and a person’s diet. It is also strongly associated with visceral-fat mass, thereby illustrating potential mechanisms underlying the well-established microbial influence on abdominal obesity.

In an earlier study, the researchers looked at the association between omega 3 (found for instance in fish oil) and the gut microbiome. They discovered that omega 3 is beneficial to humans indirectly because it makes gut bacteria produce other substances (a fecal metabolite called n-carbamyl glutamate that is anti-inflammatory and good for us). 

According to the researchers, fecal metabolic profiling is a promising tool to explore links among microbiome composition, host phenotypes and heritable complex traits.

“The fecal bacteria metabolome allows us to understand the function of different bacteria in the gut. It is not just important to know what bacteria are present in the gut, but also what these bacteria do,” study co-author Cristina Menni tells NutritionInsight.

“We found that the fecal metabolome is only determined by genetics for 20 percent. This means that 80 percent of the gut microbiome is determined by the environment and hence is modifiable, for example through dietary interventions or lifestyle changes. This is good news as it means that people can actively improve their microbiome,” she says.

‘Smart toilet paper’
The growing body of research points to the modifiability of the gut microbiome composition, through dietary interventions, pre and probiotics, and opens up options for further development of so-called postbiotics – described by the involved scientists as “the bacterial products or metabolic byproducts from gut microbes that have biologic activity in our bodies.” Because of their ability to decrease inflammation and help maintain intestinal homeostasis, postbiotics may be a smart alternative to the use of whole bacteria in probiotic form. 

The researchers also suggest that their discovery of an association between the fecal metabolome and abdominal obesity opens up a range of options to improve our understanding of how the gut microbiome works.

“You could think about developing tools, such as ‘smart toilet paper’ to quickly gain a readout of their fecal metabolome and understand whether they are at risk of abdominal obesity, allowing them to undertake some interventions,” she says. “There are companies looking into this smart toilet paper, but the research is not quite there yet.”

“Moreover, it would be interesting to investigate whether the radical changes that can be made through fecal transplants from healthy donors, also work for obesity,” she concludes.

By Lucy Gunn